The technical field of this invention is surgical instruments and, in particular, inflation catheters and detachable balloon systems for implanting structures in vivo.
Balloon catheters are used in a variety of medical procedures. Balloon catheters have been used extensively in the cardiovascular area, for example, to occlude vessels in certain types of surgery and to expand blood vessels as in an angioplasty procedure. Inflation catheters carrying detachable balloons have been used to treat urinary incontinence as disclosed in, e.g., U.S. Pat. No. 4,832,680, issued May 23, 1989; U.S. Pat. No. 4,802,479, issued Feb. 7, 1989; and U.S. Pat. No. 4,773,393, issued Feb. 27, 1988. These patents describe an extensible, inflatable containment membrane which is implanted between the urethra and the subcutaneous corpus spongiousum of a patient to overcome urinary incontinence.
Inflation catheters carrying detachable balloons have also been used in endoscopic or cystoscopic methods to treat vesicouretal reflux. In such a procedure, described in U.S. Pat. No. 5,304,123, a needle is directed through a cystoscope and inserted into the subureteral region of a refluxing bladder to establish a pocket. A catheter or similar delivery device can be inserted into this pocket in the subureteral region carrying a balloon. The balloon can then be inflated and sealed. In one embodiment, the balloon is delivered on an inflation catheter through the cystoscopic needle. The uninflated balloons must be sized to fit on the tip of the catheter and for delivery within the cystoscopic needle. Once delivered to the desired area within a patient""s body, the balloon is inflated or filled with a biocompatible material supplied through the catheter. The catheter is then withdrawn leaving the balloon in place. Preferably, the balloon includes a sealing mechanism so that the balloon seals itself upon inflation and removal of the catheter.
Additional endoscopic procedures involving inflation catheters with detachable balloons are disclosed in U.S. Pat. No. 5,411,475, issued May 2, 1995. According to this patent, a scope is provided for directly visualizing a target site in vivo. The scope includes a viewing means, a sheath, and a positioning element extending through the sheath. An uninflated, detachable balloon attached to a catheter is passed through the lumen of the positioning device, such as a hollow needle, to the target site. The balloon is then inflated and detached at the target site. The disclosed system and method can be used in a variety of medical procedures including birth control procedures.
Balloons useful in these procedures must be very small. In some procedures, a 19 gauge needle small enough to fit within standard cystoscopic equipment is used as a cystoscopic positioning device. In one system, a thin walled cystoscopic needle has a 19 gauge outer diameter and has an inner diameter of a standard 18 gauge needle (i.e., 0.036 inches). Accordingly, a balloon useful for such procedures must be readily passable though the inner lumen of this needle. The balloon is also preferably selfsealing upon inflation and detachment from the catheter. The balloon should also be detachable from the catheter with a detachment force that is appropriate to the application. The detachment force must be high enough to allow the balloon to inflate without premature detachment, and low enough to allow the catheter to be readily withdrawn without dislodging the inflated balloon from the target site.
One example of a balloon known in the art is provided in U.S. Pat. No. 4,819,637, issued Ap. 11, 1989. This balloon includes a valve base having a smooth surface cylindrical bore extending therethrough for attachment to a catheter and a xe2x80x9cduck-billxe2x80x9d type valve attached to the valve base. An additional detachable balloon is described in U.S. Pat. No. 4,832,680. That balloon is apparently larger than balloons delivered through a cystoscopic needle (it is delivered through a trocar) and includes a solid valve core that is prestressed by a surrounding compression band and a needle stop. The core and compression band are also surrounded by titanium tubing that forms a needle stop to prevent damage to the balloon. The balloon membrane is bonded to the compression band.
Known balloons perform poorly when miniaturized for delivery through small lumens, such as a cystoscopic needle, or they are expensive to make in miniature or both. Accordingly, it is an object of the present invention to provide a low cost, easy to manufacture, highly efficient miniature balloon for detachable delivery in vivo.
The invention provides a detachable balloon system including an inflatable balloon having a self-sealing valve. The balloon has an elastomeric membrane and a proximal opening. The self-sealing valve is made up of a valve body for receiving an inflation instrument to inflate the balloon. The valve body is preferably formed of a biocompatible elastomeric material and includes a base portion and a sealing portion. The base portion is bonded to the elastomeric membrane so as to seal the proximal opening of the balloon. The sealing portion is positioned internally within the balloon membrane and extends distally from the base portion into the balloon. The sealing portion is compressibly sealable in response to a pressure within the balloon following inflation of the balloon and removal of an inflation instrument.
The size of the self-sealing balloon and valve of the invention may readily be scaled down for even the smallest applications while maintaining an ease of manufacture that is unknown in the art. In addition, the balloon and valve of the invention can reliably reseal after removal of an inflation instrument, even under high inflation pressure conditions, regardless of balloon size.
In one embodiment, the base and sealing portions of the valve body are both cylindrical and the sealing portion has a smaller diameter than the base. A guide opening can also be formed in the proximal surface of valve body for guiding an inflation instrument to the center of the valve body. The valve body may also be provided with a pierce, slit or other opening extending longitudinally therethrough. A guide portion may also be provided on the valve body integrally formed with and proximal to the base. When the guide portion has a larger diameter than the base, a distal facing ledge, convenient for locating the balloon with respect to the valve body, is provided on the guide portion.
Generally, the benefits provided by the detachable balloon of the invention are greatest where the balloon has an uninflated diameter of about 0.010 to 0.125 inches and more preferably where the uninflated diameter of the balloon is no greater than about 0.060 inches (including uninflated diameters of less than 0.010 inches). Balloons of the invention may generally have a filled volume of about 10 ccs or less, and more preferably about 0.1 to 1.0 ccs.
A balloon dispenser for housing a balloon prior to receipt of an inflation instrument is also provided. The balloon dispenser includes a balloon seating element sized to allow the balloon to rest in the seating element, a guideway channel for guiding an inflation instrument into mating alignment with the balloon, and an element responsive to external pressure for holding the balloon steady against longitudinal movement with respect to the inflation instrument. In one embodiment, the element responsive to external pressure for holding the balloon includes a solid portion proximate to the balloon and being deflectable in response to external pressure so as to compress the balloon into the balloon seating element.